In many industries, abrasive brushes are used to prepare and/or finish materials. The brushes are typically mounted on cylindrical hubs which are rotated during a finishing operation.
A typical industrial cylinder brush arrangement utilizes, as the rotatable hub, a slotted hub construction. In general, slotted hubs comprise elongate cylinders having a plurality of longitudinal slots evenly spaced around the outer surface of the cylinders. Each slot is sized and oriented for anchoring of one or more brush segments thereto. By convention, the number of slots around the outer surface of a cylinder generally comprises five times the diameter (in inches) of the hub; the conventional diameters for hubs generally being 3, 4, 6, 8, 10, 12 and 14 inches (i.e. about 7.6; 10.2; 15.2; 20.3; 25.4; 30.5; and, 35.6 cm respectively).
In many conventional applications of longitudinal slotted hubs, each brush segment is mounted by means of a single elongate root member. The root members are such that each brush segment is capable of some hinge-like movement or pivoting movement (i.e., gating, rocking or flapping) with respect to the hub, during use.
A conventional abrasive member or segment is depicted in FIGS. 1 and 2. In particular, the reference numeral 1, FIG. 1, depicts a conventional brush segment, such as available under the trade designation "Brushlon", from Minnesota Mining and Manufacturing Company, Saint Paul, Minn. 55144 (3M). Segment 1 is of a type utilizable with a conventional cylinder hub, such as an "RX" brand aluminum hub, also available under the trade designation "Brushlon" or "Brushlon/RX", from 3M.
Segment 1 generally comprises a root 2, scrim wrapped section (fiber pack) 3, and bristles or fibers 4. In general, root 2 is configured for engagement with slots, on a slotted hub. Scrim wrapped section 3 secures ends of fibers 4 in position. Scrim wrapped section 3 is mechanically mounted on root 2, by staples 6 which extend completely through the segment 1. For a typical long trim brush segment (before wear during use), fibers 4 will have a length of extension, out of scrim wrapped section 3, of at least about 2 inches (at least about 5 cm), and typically at least about 3-12 inches (i.e. about 7.5-30.5 cm). Referring to FIG. 2, root 2 includes an expanded base portion (bottom bead or ball portion) 10 and a neck portion 11. As will be understood by reference to FIG. 2, brush segment 1 generally has two packs or sections of scrim 3 (with fibers 4 mounted therein) one on each side of neck portion 11. These are indicated generally at reference numerals 12 and 13, respectively.
Each of sections 12 and 13 comprises a fold of scrim material 14 with ends of fibers 4 projecting thereinto. The fibers 4 are held in place by cores of hot melt resin 15 received within scrim material 14. A conventional hot melt resin utilized for this purpose is polyamide thermoplastic.
Brush segments such as those illustrated in FIGS. 1 and 2 have been utilized in a variety of environments. However, they are subject to loss of bristles or fibers therefrom, especially when used in wet or caustic environments, or with organic solvent solutions. Also, the staples 6 and scrim material 14 occupy width which is wasted, i.e., not occupied by the presence of bristles. Further, end 16 of root 2, FIG. 2, generates a space 17 which is wasted in a similar manner, because the sections of bristles (12 and 13) must be anchored on opposite sides of neck 11. That is, due to space 17, brush segment 1 is a low density brush.